From the neighbourhood of Potenza, the main ridge of the Apennines is continued by the Monti della Maddalena in a direction nearly due south, so that it approaches within a short distance of the Gulf of Policastro, whence it is carried on as far as the Monte Pollino, the last of the lofty summits of the Apennine chain, which exceeds 7000 ft. in height. The range is, however, continued through the province now called Calabria, to the southern extremity or “toe” of Italy, but presents in this part a very much altered character, the broken limestone range which is the true continuation of the chain as far as the neighbourhood of Nicastro and Catanzaro, and keeps close to the west coast, being flanked on the east by a great mass of granitic mountains, rising to about 6000 ft., and covered with vast forests, from which it derives the name of La Sila. A similar mass, separated from the preceding by a low neck of Tertiary hills, fills up the whole of the peninsular extremity of Italy from Squillace to Reggio. Its highest point is called Aspromonte (6420 ft.).
While the rugged and mountainous district of Calabria, extending nearly due south for a distance of more than 150 m., thus derives its character and configuration almost wholly from the range of the Apennines, the long spur-like promontory which projects towards the east to Brindisi and Otranto is merely a continuation of the low tract of Apulia, with a dry calcareous soil of Tertiary origin. The Monte Volture, which rises in the neighbourhood of Melfi and Venosa to 4357 ft., is of volcanic origin, and in great measure detached from the adjoining mass of the Apennines. Eastward from this the ranges of low bare hills called the Murgie of Gravina and Altamura gradually sink into the still more moderate level of those which constitute the peninsular tract between Brindisi and Taranto as far as the Cape of Sta Maria di Leuca, the south-east extremity of Italy. This projecting tract, which may be termed the “heel” or “spur” of Southern Italy, in conjunction with the great promontory of Calabria, forms the deep Gulf of Taranto, about 70 m. in width, and somewhat greater depth, which receives a number of streams from the central mass of the Apennines.
None of the rivers of Southern Italy is of any great importance. The Liri (Liris) or Garigliano, which has its source in the central Apennines above Sora, not far from Lake Fucino, and enters the Gulf of Gaeta about 10 m. east of the city of that name, brings down a considerable body of water; as does also the Volturno, which rises in the mountains between Castel di Sangro and Agnone, flows past Isernia, Venafro and Capua, and enters the sea about 15 m. from the mouth of the Garigliano. About 16 m. above Capua it receives the Calore, which flows by Benevento. The Silarus or Sele enters the Gulf of Salerno a few miles below the ruins of Paestum. Below this the watershed of the Apennines is too near to the sea on that side to allow the formation of any large streams. Hence the rivers that flow in the opposite direction into the Adriatic and the Gulf of Taranto have much longer courses, though all partake of the character of mountain torrents, rushing down with great violence in winter and after storms, but dwindling in the summer into scanty streams, which hold a winding and sluggish course through the great plains of Apulia. Proceeding south from the Trigno, already mentioned as constituting the limit of Central Italy, there are (1) the Biferno and (2) the Fortore, both rising in the mountains of Samnium, and flowing into the Adriatic west of Monte Gargano; (3) the Cervaro, south of the great promontory; and (4) the Ofanto, the Aufidus of Horace, whose description of it is characteristic of almost all the rivers of Southern Italy, of which it may be taken as the typical representative. It rises about 15 m. west of Conza, and only about 25 m. from the Gulf of Salerno, so that it is frequently (though erroneously) described as traversing the whole range of the Apennines. In its lower course it flows near Canosa and traverses the celebrated battlefield of Cannae. (5) The Bradano, which rises near Venosa, almost at the foot of Monte Volture, flows towards the south-east into the Gulf of Taranto, as do the Basento, the Agri and the Sinni, all of which descend from the central chain of the Apennines south of Potenza. The Crati, which flows from Cosenza northwards, and then turns abruptly eastward to enter the same gulf, is the only stream worthy of notice in the rugged peninsula of Calabria; while the arid limestone hills projecting eastwards to Capo di Leuca do not give rise to anything more than a mere streamlet, from the mouth of the Ofanto to the south-eastern extremity of Italy.
The only important lakes are those on or near the north frontier, formed by the expansion of the tributaries of the Po. They have been already noticed in connexion with the rivers by which they are formed, but may be again enumerated in order of Lakes. succession. They are, proceeding from west to east, (1) the Lago d’Orta, (2) the Lago Maggiore, (3) the Lago di Lugano, (4) the Lago di Como, (5) the Lago d’Iseo, (6) the Lago d’Idro, and (7) the Lago di Garda. Of these the last named is considerably the largest, covering an area of 143 sq. m. It is 32¼ m. long by 10 broad; while the Lago Maggiore, notwithstanding its name, though considerably exceeding it in length (37 m.), falls materially below it in superficial extent. They are all of great depth—the Lago Maggiore having an extreme depth of 1198 ft., while that of Como attains to 1365 ft. Of a wholly different character is the Lago di Varese, between the Lago Maggiore and that of Lugano, which is a mere shallow expanse of water, surrounded by hills of very moderate elevation. Two other small lakes in the same neighbourhood, as well as those of Erba and Pusiano, between Como and Lecco, are of a similar character.
The lakes of Central Italy, which are comparatively of trifling dimensions, belong to a wholly different class. The most important of these, the Lacus Fucinus of the ancients, now called the Lago di Celano, situated almost exactly in the centre of the peninsula, occupies a basin of considerable extent, surrounded by mountains and without any natural outlet, at an elevation of more than 2000 ft. Its waters have been in great part carried off by an artificial channel, and more than half its surface laid bare. Next in size is the Lago Trasimeno, a broad expanse of shallow waters, about 30 m. in circumference, surrounded by low hills. The neighbouring lake of Chiusi is of similar character, but much smaller dimensions. All the other lakes of Central Italy, which are scattered through the volcanic districts west of the Apennines, are of an entirely different formation, and occupy deep cup-shaped hollows, which have undoubtedly at one time formed the craters of extinct volcanoes. Such is the Lago di Bolsena, near the city of the same name, which is an extensive sheet of water, as well as the much smaller Lago di Vico (the Ciminian lake of ancient writers) and the Lago di Bracciano, nearer Rome, while to the south of Rome the well known lakes of Albano and Nemi have a similar origin.
The only lake properly so called in southern Italy is the Lago del Matese, in the heart of the mountain group of the same name, of small extent. The so-called lakes on the coast of the Adriatic north and south of the promontory of Gargano are brackish lagoons communicating with the sea.
The three great islands of Sicily, Sardinia and Corsica are closely connected with Italy, both by geographical position and community of language, but they are considered at length in separate articles. Of the smaller islands that lie near the coasts Islands. of Italy, the most considerable is that of Elba, off the west coast of central Italy, about 50 m. S. of Leghorn, and separated from the mainland at Piombino by a strait of only about 6 m. in width. North of this, and about midway between Corsica and Tuscany, is the small island of Capraia, steep and rocky, and only 4½ m. long, but with a secure port; Gorgona, about 25 m. farther north, is still smaller, and is a mere rock, inhabited by a few fishermen. South of Elba are the equally insignificant islets of Pianosa and Montecristo, while the more considerable island of Giglio lies much nearer the mainland, immediately opposite the mountain promontory of Monte Argentano, itself almost an island. The islands farther south in the Tyrrhenian Sea are of an entirely different character. Of these Ischia and Procida, close to the northern headland of the Bay of Naples, are of volcanic origin, as is the case also with the more distant group of the Ponza Islands. These are three in number—Ponza, Palmarola and Zannone; while Ventotene (also of volcanic formation) is about midway between Ponza and Ischia. The island of Capri, on the other hand, opposite the southern promontory of the Bay of Naples, is a precipitous limestone rock. The Aeolian or Lipari Islands, a remarkable volcanic group, belong rather to Sicily than to Italy, though Stromboli, the most easterly of them, is about equidistant from Sicily and from the mainland.
The Italian coast of the Adriatic presents a great contrast to its opposite shores, for while the coast of Dalmatia is bordered by a succession of islands, great and small, the long and uniform coast-line of Italy from Otranto to Rimini presents not a single adjacent island; and the small outlying group of the Tremiti Islands (north of the Monte Gargano and about 15 m. from the mainland) alone breaks the monotony of this part of the Adriatic.
Geology.—The geology of Italy is mainly dependent upon that of the Apennines (q.v.). On each side of that great chain are found extensive Tertiary deposits, sometimes, as in Tuscany, the district of Monferrat, &c., forming a broken, hilly country, at others spreading into broad plains or undulating downs, such as the Tavoliere of Puglia, and the tract that forms the spur of Italy from Bari to Otranto.
Besides these, and leaving out of account the islands, the Italian peninsula presents four distinct volcanic districts. In three of them the volcanoes are entirely extinct, while the fourth is still in great activity.